A 17-acre hillside forest in Setauket, once home to potato farms, is Long Island’s newest state parkland.

“Today, time stands still; we freeze the landscape permanently in these 17 acres,” said Assemb. Steven Englebright (D-Setauket) as officials unveiled the parkland’s new plaque Friday.

The woodland is bordered by Watson Lane and Main Street. George Washington traveled through the area on April 22, 1790, to thank his spies for saving him and “his revolution,” said Englebright, chairman of the Assembly Environmental Conservation Committee.

The forest of red cedar, gray birch and poplar trees and a few invasive species, such as black locust and Norway maple, was home to potato farms until the 1950s, officials said.

The Fitzsimmons family, who still live down the hill from the new parkland, began putting the tract together after moving to North Country Road in 1939.

“The Fitzsimmons parcel is the final piece in a puzzle that the community and its elected officials have been working on for nearly two decades,” said Suffolk Deputy County Executive Peter A. Scully.

While serving as Long Island regional DEC director, Scully helped drive the acquisition of Patriots Hollow State Forest, the location of Patriot’s Rock. The boulder shielded Washington’s troops while they fired on the British in 1772, local experts say.

Several speakers stressed that the new parkland fulfills dual goals of protecting the environment and ensuring history is not forgotten. “Nothing reinforces the integrity of an historic district like open space,” said Robert Reuter, a member of Brookhaven’s Historic District Advisory Committee.

The state drew on environmental protection funds for the purchase, and Englebright saluted the Fitzsimmons’ generosity, as they probably could have obtained a higher price had they let developers bid on the land.

Instead, “they waited patiently as many of us put the resources in place to fairly compensate them for their many decades of work,” he said.

The forest could open for hikers after trails are cleared as soon as next spring or summer, said DEC Long Island regional director Carrie Meek Gallagher.